Implants/Procedures Related to Tibial Tuberosity Advancement

ABSTRACT

A tibial tuberosity advancement (TTA) system is configured to maintaining a tuberosity in an advanced position relative to a tibial body. The TTA system includes an implant, a spacer, and a spacer fixation member.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims benefit to U.S. Provisional Application No.61/659,655, filed Jun. 14, 2012, the disclosure of which is herebyincorporated by reference herein in its entirety.

TECHNICAL FIELD

The present application generally relates to systems, apparatus, andmethods for stabilizing a deficient stifle, and more particularly, tosystems, apparatus, and methods for performing a tibial tuberosityadvancement procedure.

BACKGROUND

Referring to FIG. 1, the knee joint 20 of quadrupeds, such as dogs andcats, connects the tibia 22 and the femur 24 in a pivotal relationship.The knee joint 20 includes a number of stabilizing tendons and ligamentsthat supports the joint during anatomical function. For instance, thecranial cruciate ligament (CCL), similar to the anterior cruciateligament in humans, bears the majority of the animal's weight, and isimportant to the overall stability of the knee joint 20. The CCL isattached to the tibia 22 and the femur 24, and in general prevents orlimits sliding of the tibia 22 forward or cranially relative to thefemur 24, and further limits internal rotation of the tibia 22 relativeto the femur 24 as well as hyperextension of the knee joint 20. The kneejoint 20 further includes a meniscus 26 that is disposed between thetibia 22 and the femur 24, and absorbs impact and provides a glidingsurface between the femur 24 and tibial plateau 28 of the tibia 22.

The tibia 22 includes a tibial body 23 and a tuberosity 30 that extendsfrom the tibial body 23. The patellar tendon 32 is anchored between thetuberosity 30 and the femur 24. As illustrated in FIG. 1, a line 27extending through the patellar tendon 32 that is both normal to thepatellar tendon and directed toward the tibial plateau 28 is angularlyoffset with respect to a line 29 that lies in the plane generallydefined by the tibial plateau 28, and intersects the line 27 at alocation between the patellar tendon 32 and the tibial plateau 28.Accordingly, when the CCL is damaged, which is a common injury incanines, the patellar ligament 32 does not prevent the femur 24 fromtravelling along the tibial plateau 28 due to tibiofemoral sheer forceswhen weight is applied to the injured knee join 20. As a result, damageto the CCL often results in lameness of the affected knee, damage to themeniscus 26 due to forces applied by the femur 24, and degenerativejoint diseases. Furthermore, the animal can tend to overcompensate forthe injured knee joint 20, which can result in rupture of the CCL of theother knee during a weight-bearing anatomical function.

Referring also to FIG. 2, tibial tuberosity advancement (TTA) is aprocedure designed to repair a knee joint 20 that has been affected by adamaged cranial cruciate ligament. Conventional TTAs include the step ofperforming an osteotomy cut to separate the tibial tuberosity 30 fromthe tibial body 23, and subsequently advancing the tibial tuberosity 30,and thus also the patellar tendon 32, cranially to a position spacedfrom the tibia 22 so as to define a gap 40 between the tibial tuberosity30 and the tibial body 23. For instance, during a TTA, the tibialtuberosity 30 and the patellar tendon 32 are typically advanced suchthat the line 27 extending through the patellar tendon 32 that is bothnormal to the patellar tendon 32 and directed toward the tibial plateau28 is also substantially parallel to, and can be coincident with, theline 29 that lies in the plane generally defined by the tibial plateau28. Thus, the line 27 can be substantially parallel to or coincidentwith the plane defined by the tibial plateau 28. In general, the line 27is more parallel to, or coincident with, the line 29, and thus the planedefined by the tibial plateau 28, after the TTA than before the TTA. Thetibial tuberosity 30 is then fixed in the advanced position, whichneutralizes the tibiofemoral sheer force when weight is applied to theknee joint 20, thereby reducing or altogether bypassing the anatomicalfunction of the CCL.

Thus, with continuing reference to FIG. 2, a conventional TTA system 34includes a bone plate 36 that is connected to the tibia 22 at one end,and to the advanced tibial tuberosity 30 at another end so as to providefixation of the advanced tibial tuberosity 30 and the tibial body 23,and a spacer 38 in the form of a cage that is separate from the boneplate 36 and is disposed and connected between the advanced tibialtuberosity 30 and the tibial body 23 so as to maintain the gap 40between the tibial tuberosity 30 and the tibial body 23 against thecaudally-directed force of the patellar tendon 32.

A number instruments, apparatus, systems, and methods have beendeveloped to conduct TTA procedures in dogs. However, improvements tothose instruments and implants are still desired.

SUMMARY

The present disclosure relates to TTA systems for maintaining anadvanced tuberosity in an advanced position relative to a tibial body.The advanced position of the tuberosity is spaced cranially andproximally with respect to a first position when the tuberosity isintegral with the tibial body. In one embodiment, the TTA systemgenerally includes an implant, a spacer, and a spacer fixation member.The implant includes an implant body that defines a proximal end portionthat configured to support the advanced tuberosity in the advancedposition, a distal end portion that is configured to be attached to thetibial body, and an intermediate implant portion that extends betweenthe proximal end portion and distal end portion. The intermediateportion is shaped so as to space the proximal end cranially andproximally with respect to the distal end portion an amount, or adistance, sufficient so as to maintain the advanced tuberosity in theadvanced position. The spacer is configured and sized to fit within agap disposed between the advanced tuberosity and the tibial body 23 whenthe distal end portion and the proximal end portion are attached to thetibial body 23 and the advanced tuberosity, respectively. The spacerincludes a spacer body, and defines a slot that extends through thespacer body. The spacer fixation member includes a first end portionconfigured to be attached to the advanced tuberosity, a second endportion that is configured to be attached to the tibial body, and anintermediate fixation portion extending between the first end and thesecond end. The intermediate fixation portion is configured and sized tobe at least partially received in the slot so as to couple the spacerfixation member to the spacer.

The present disclosure further relates to TTA advancement assembliesthat are configured to advance a tuberosity from a first position to anadvanced position relative to a tibial body after an osteotomy has beenmade between the tuberosity and the tibial body. In an embodiment, theTTA advancement assembly includes an advancement body that is configuredto be coupled to the tibial body, and a distraction arm movably coupledto the advancement body. The distraction arm is configured to be coupledto the tuberosity, and is configured to translate to move along with thetuberosity relative to the tibial body, such that the distraction armmoves a predetermined distance relative to the advancement body. Thetranslation of the distraction arm over the predetermined distancecauses the advancement assembly to provide an indication that thetuberosity has advanced from the first position to the advancedposition.

In an embodiment, the TTA advancement assembly includes an advancementbody that is configured to be coupled to the tibial body; and an angularadjustment member pivotally coupled to the advancement body. The angularadjustment member is configured to pivot relative to the advancementbody about a pivot axis, and includes a contact member that isconfigured to fit in a gap defined by the osteotomy. The angularadjustment member is configured to be pivotally fixed relative to theadvancement body such that the advancement body is oriented at apredetermined advancement angle relative to the osteotomy when thecontact member is disposed in the osteotomy.

The present disclosure further relates to TTA methods for advancing atuberosity from a first position to an advanced position relative to atibial body after an osteotomy has been made between the tuberosity andthe tibial body. In an embodiment, the TTA method includes one or moreof the following steps: a) coupling an advancement body to thetuberosity via a distraction arm that is movably coupled to theadvancement body, the distraction arm configured to translate relativeto the advancement body; b) placing a contact member that is coupled tothe advancement body in a gap formed during the osteotomy, the gapdisposed between the tuberosity and the tibial body; c) moving thedistraction arm relative to the advancement body to move the tuberositybetween the first position and the advanced position.

BRIEF DESCRIPTION OF THE DRAWINGS

The foregoing summary, as well as the following detailed description ofa preferred embodiment, are better understood when read in conjunctionwith the appended diagrammatic drawings. For the purpose of illustratingthe invention, the drawings show an embodiment that is presentlypreferred. The invention is not limited, however, to the specificinstrumentalities disclosed in the drawings. In the drawings:

FIG. 1 is an illustration of a healthy knee of a canine;

FIG. 2 is a side elevation view of a conventional tibial tuberosityadvancement system implanted in the knee illustrated in FIG. 1, forinstance in response to an injury to the cranial cruciate ligament ofthe knee;

FIG. 3 is a perspective view of at least part of a Tibial TuberosityAdvancement (TTA) system in accordance with an embodiment of the presentdisclosure, the TTA system including a spacer, a spacer fixation member,and an implant;

FIG. 4A is a perspective view of a spacer in accordance with anembodiment of the present disclosure;

FIG. 4B is a front elevation view of the spacer shown in FIG. 4A;

FIG. 4C is a top view of the spacer shown in FIG. 4A;

FIG. 4D is a side cross-sectional view of the spacer shown in FIG. 4A,taken along section line 4D-4D;

FIG. 4E is a sectional view of the spacer shown in FIG. 4A, taken alongsection line 4D-4D;

FIG. 4F is a perspective view of a spacer in accordance with oneembodiment;

FIG. 4G is a perspective view of a spacer in accordance with anotherembodiment;

FIG. 4H is a perspective view of a spacer in accordance with anotherembodiment;

FIG. 4I is a perspective view of a spacer in accordance with anotherembodiment;

FIG. 4J is a perspective view of a spacer in accordance with anotherembodiment;

FIG. 4K is a perspective view of a spacer in accordance with anotherembodiment;

FIG. 4L is a perspective view of a spacer in accordance with anotherembodiment;

FIG. 5A is a perspective view of the spacer fixation member shown inFIG. 3;

FIG. 5B is a perspective view of a spacer fixation member in accordancewith another embodiment;

FIG. 6A is a perspective exploded view of a spacer in accordance withanother embodiment, the spacer fixation member shown in FIG. 5B, and afastener;

FIG. 6B is a perspective view of the spacer, the spacer fixation member,and the fastener shown in FIG. 6A connected to each other;

FIG. 6C is a front elevation view of the spacer shown in FIG. 6A;

FIG. 7A is a perspective view of a spacer in accordance with oneembodiment and a fastener;

FIG. 7B is a front elevation view of the spacer and the fastener shownin FIG. 7A;

FIG. 8A is a perspective view of a guide assembly configured to guidethe advancement of a tuberosity relative to a tibial body, the spacershown in FIG. 3, the spacer fixation member shown in FIG. 3, and theimplant shown in FIG. 3, wherein the guide assembly is coupled to theadvanced tuberosity and the tibial body;

FIG. 8B is a perspective view of the guide assembly shown in FIG. 8A;

FIG. 8C is a perspective exploded view of the guide assembly shown inFIG. 8A;

FIG. 9 is a schematic representation of a common tangent method fordetermining the longitudinal and angular advancement of the tuberosityrelative to the tibial body;

FIG. 10A is a top, rear perspective view of an implant in accordancewith another embodiment;

FIG. 10B is a bottom, front perspective view of the implant shown inFIG. 10A;

FIG. 10C is a left side elevation view of the implant shown in FIG. 10Ain a first orientation;

FIG. 10D is a right side elevation view of the implant shown in FIG.10A;

FIG. 10E is a left side elevation view of the implant shown in FIG. 10Ain a second orientation;

FIG. 10F is a top plan view of the implant shown in FIG. 10A;

FIG. 10G is a bottom plan view of the implant shown in FIG. 10A;

FIG. 10H is a front elevation view of the implant shown in FIG. 10F, inthe direction of line 10H;

FIG. 10I is a rear elevation view of the implant shown in FIG. 10F, inthe direction of line 10I;

FIG. 11A is a top, rear perspective view of an implant in accordancewith another embodiment;

FIG. 11B is a bottom, front perspective view of the implant shown inFIG. 11A;

FIG. 11C is a left side elevation view of the implant shown in FIG. 11Ain a first orientation;

FIG. 11D is a right side elevation view of the implant shown in FIG.11A;

FIG. 11E is a left side elevation view of the implant shown in FIG. 11Ain a second orientation;

FIG. 11F is a top plan view of the implant shown in FIG. 11A;

FIG. 11G is a bottom plan view of the implant shown in FIG. 11A;

FIG. 11H is a front elevation view of the implant shown in FIG. 11F, inthe direction of line 11H;

FIG. 11I is a rear elevation view of the implant shown in FIG. 11F, inthe direction of line 11I.

DETAILED DESCRIPTION OF THE DRAWINGS

Certain terminology is used in the following description for convenienceonly and is not limiting. The words “right”, “left”, “lower” and “upper”designate directions in the drawings to which reference is made. Thewords “medially” and “laterally” refer to directions toward and awayfrom, respectively, a midline extending through a body, for example froma head to a tail of a canine body. The words “proximal” and “distal”refer to directions toward or away from where an appendage is joined tothe rest of the body. The words “anterior”, “posterior”, “dorsal”,“ventral” and related words and/or phrases designate preferred positionsand orientations in the canine body to which reference is made and arenot meant to be limiting. For example “anterior” and “posterior” referto positions closer to the head and tail, respectively. While “dorsal”and “ventral” refer to positions closer to the spinal column and thebelly, respectively. The terminology includes the above-listed words,derivatives thereof and words of similar import. For example, as shownin FIG. 8A, the arrow 60 may represent the proximal, dorsal, or upwarddirection. The arrow 62 may represent the distal, ventral, or downwarddirection. The arrow 64 may represent the front, cranial or anteriordirection. The arrow 66 may represent the caudal, rear or posteriordirection. The arrow 68 may represent the lateral or away direction. Thearrow 70 may represent the medial or toward direction.

With reference to FIG. 3, a Tibial Tuberosity Advancement (TTA) system100 can be configured to stabilize cranial cruciate ligament-deficientstifles in quadrupeds. In one embodiment, the TTA system 100 includes animplant 104, such as a tibial tuberosity advancement (TTA) implant, fora quadruped. The implant 104 can be constructed as a bone fixationmember 106, such as a bone plate 108. In the depicted embodiment, theimplant 104 includes an implant body 110 that includes a proximal endportion 112, an opposed distal end portion 114, and an intermediateimplant portion 116 disposed between the proximal end portion 112 andthe distal end portion 114.

The proximal end portion 112 of the implant body 110 can be configuredto be attached to the tuberosity 30 that has been advanced along withthe patellar tendon 32 (shown in FIG. 1) in a direction craniallyrelative to the tibial body 23 from a first position to an advancedposition. The distal end portion 114 of the implant body 110 can beconfigured to be attached to the tibial body 23. It should beappreciated that the patellar tendon 32 is attached to the tuberosity 30at an anatomical attachment location 43, and that the tuberosity 30 canbe resected, and thus separated, from the tibial body 23 at a locationcaudal of the attachment location 43 such that the patellar tendon 32,including the attachment location 43, is advanced along with theseparated tuberosity 30 from the first position to the advancedposition. The proximal end portion 112, the distal end portion 114, andthe intermediate implant portion 116 can collectively be a monolithicstructure. Alternatively, proximal end portion 112, the distal endportion 114, and the intermediate implant portion 116 can be discretecomponents that are connected to each other to form the implant body110.

The proximal end portion 112 can be contoured and configured to conformto a medial surface or lateral surface of the tuberosity 30 tofacilitate attachment of the implant 104 to the tuberosity 30. Moreover,the proximal end portion 112 includes one or more attachment locationssuch as fastener holes. In the depicted embodiment, the proximal endportion 112 of the implant body 110 includes four fastener holes 118 a,118 b, 118 c, and 118 d. However, the proximal end portion 112 mayinclude more or fewer fastener holes. Irrespective of the specificnumber of fastener holes, each fastener hole 118 a, 118 b, 118 c, and118 d extends through the implant body 110, and is configured and sizedto receive a fastener 120, such as a bone anchor, that is capable ofattaching the implant 104 to the tuberosity 30.

Examples of suitable fasteners 120 include, but are not limited to, bonescrews, nails, pins, and any other apparatus that is configured toattach the implant 104 to the tuberosity 30. For instance, the fastenerholes 118 a, 118 b, 118 c, and 118 d can be threaded holes that areconfigured to receive a bone screw. Furthermore, the fasteners holes 118a, 118 b, 118 c, and 118 d can be conical thread holes that areconfigured receive bone screws with a threaded conical head. Theinsertion of fasteners 120 through fastener holes 118 a, 118 b, 118 c,and 118 d causes the proximal end portion 112 to be attached to thetuberosity 30. The fastener holes 118 a, 118 b, 118 c, and 118 d may bespaced apart from one another and substantially aligned along a firstlongitudinal axis L1 that extends substantially parallel to thedirection of elongation of the tuberosity 30 when the implant 104 isattached to the advanced tuberosity 30. In one embodiment the proximalend portion 112 can be elongate along the longitudinal axis L1.

The distal end portion 114 can be contoured and configured to conform toa medial surface or a lateral surface of the tibial body 23 tofacilitate attachment of the implant 104 to the tibial body 23. Further,the distal end portion 114 of the implant body 110 can include one ormore anchor locations such as fastener holes. In the depictedembodiment, the distal end portion 114 includes a first fastener hole122 a and a second fastener hole 122 b. Each of the fastener holes 122 aand 122 b can be configured and sized to receive a fastener 124, such asa bone anchor, capable of attaching the implant 104 to the tibial body23.

Examples of suitable fasteners 124 include, but are not limited to, bonescrews, nails, pins, and any other apparatus that is configured toattach the implant 104 to the tibial body 23. The insertion of fasteners124 through the fastener holes 122 a and 122 b causes the distal endportion 114 to be attached to the tibial body 23. The fastener holes 122a and 122 b may be spaced apart from one another and substantiallyaligned along a second longitudinal axis L2. In one embodiment thedistal end portion 114 can be elongate along the second longitudinalaxis L2. The second longitudinal axis L2 may be angularly offset fromthe first longitudinal axis L1.

The intermediate implant portion 116 of the implant body 110 can beelongated along the second longitudinal axis L2. Alternatively, theintermediate implant portion 116 may be elongated along an axis that isangularly offset from the second longitudinal axis L2. Although thedrawings do not show attachment locations, such as fastener holes, inthe intermediate implant portion 116, it is envisioned that theintermediate implant portion 116 may include one or more fastener holesor any other suitable attachment feature. The intermediate implantportion 116 extends between the proximal end portion 112 and the distalend portion 114 and is shaped so as to space the proximal end portion112 cranially with respect to the distal end portion 114 an amount, or adistance, sufficient so as to maintain the tuberosity 30 in the advancedposition.

The TTA system 100 can further include a spacer 102 configured tomaintain a distance between the tibial body 23 and the tuberosity 30when the tuberosity 23 is in the advanced position. The spacer 102 canbe configured and sized to at least partially fit in the osteotomy gap40 defined between the tibial body 23 and the advanced tuberosity 30. Inthe depicted embodiment, the spacer 102 can be configured as a cage 126as described in detail below.

Aside from the spacer 102, the TTA system 100 can include a spacerfixation member 128 that is configured to couple the spacer 102 to thetibial body 23 and the advanced tuberosity 30, thereby fixing the spacer102 in the osteotomy gap 40. As discussed in detail below, the spacerfixation member 128 can be configured as a bone plate 130. At least aportion of the bone plate 130 can be configured and sized to be insertedthrough the spacer 102. The spacer fixation member 128 includes a body134, which is also referred to as a plate body. The body 134 of thespacer fixation member 128 can be elongated, and can define first endportion 138, a second end portion 140, and an intermediate fixationportion 142 (shown in FIG. 5A) disposed between the first end portion138 and the second end portion 140.

The first end portion 138 can be configured to be attached to theadvanced tuberosity 30. To this end, the first end portion 138 can becontoured and configured to conform to a lateral surface or a medialsurface of the advanced tuberosity 30, and can include one or moreattachment locations such as fastener holes 132. The fastener holes 132can be configured and sized to receive a fastener 136, such as a boneanchor, capable of attaching the spacer fixation member 128 to theadvanced tuberosity 30. Suitable fasteners 136 include, but are notlimited to, bone screws, nails, pins, or any other fastener 136 that canattach the first end portion 138 to the advanced tuberosity 30.

The second end portion 140 of the body 134 is configured to be attachedto the tibial body 23. To this end, the second end portion 140 can becontoured and configured to conform to a lateral surface or a medialsurface of the tibial body 23, and can include one or more attachmentlocations such as fastener holes 144. In the depicted embodiment, thesecond end portion 140 includes only one fastener hole 144; however, itis envisioned that the second end portion 140 can define more than onefastener hole 144. The fastener hole 144 can be configured and sized toreceive a fastener 136, such as bone anchors. Examples of fasteners 136include, but are not limited to, bone screws, nails, pins or any otherapparatus that can attach the second end portion 140 to the tibial body23.

The intermediate fixation portion 142 is configured to be insertedthrough an opening, such as a slot, of the spacer 102 in order to securethe spacer 102 in the osteotomy gap 40 when the first end portion 138 isattached to the advanced tuberosity 30 and the second end is attached tothe tibial body 23. In the depicted embodiment, the intermediatefixation portion 142 can have a substantially planar configuration asdescribed in detail below. The first end portion 138, the second endportion 140, and the intermediate fixation portion 142 can be amonolithic structure. Alternatively, the first end portion 138, thesecond end portion 140, and the intermediate fixation portion 142 can bediscrete components connected to one another. The intermediate fixationportion 142 can define a substantially planar configuration that isconfigured to fit within a slot of the spacer 102 as discussed below.

With reference to FIGS. 4A-4E, the spacer 102 can include a spacer body148 configured and sized to fit in the osteotomy gap 40. The spacer body148 can be elongate along a longitudinal direction 150, and can define afirst longitudinal end 152 and a second longitudinal end 154 that isspaced from the first longitudinal end 152 along the longitudinaldirection 150. Furthermore, the spacer body 148 defines a first lateralend 156 and a second lateral end 158 that is spaced from the firstlateral end 156 along a lateral direction 160. The lateral direction 160is substantially perpendicular to the longitudinal direction 150.

Specifically, the spacer body 148 may have a first transverse end 164and a second transverse end 166 that is spaced from the first transverseend 164 along the transverse direction 162. The transverse direction 162is substantially perpendicular to the longitudinal direction 150 and thelateral direction 160. In the depicted embodiment, the spacer body 148can define a substantially partial wedge shape such that its widthincreases in the transverse direction 162. The width of the spacer body148 is defined between the first lateral end 156 and the second lateralend 158. In the depicted embodiment, the spacer body 148 can define afirst width W1 at the first transverse end 164 that is greater than asecond width W2 at the second transvers end 166. The wedge-shape of thespacer body 148 facilitates insertion and positioning of the spacer 102in the osteotomy gap 40 since the osteotomy gap 40 has a substantiallywedge shape.

The spacer 102 can further include an opening 168 that extends throughspacer body 148 from the first longitudinal end 152 to the secondlongitudinal end 154. Thus, the opening 168 can be elongate along thelongitudinal direction 150. The opening 168 can be constructed as ahole, and is configured to receive bone graft or any other natural orsynthetic material capable of promoting bone growth. However, theopening 168 does not necessarily have to be filled with a bone graft orany other bone growth agent. The opening 168 provides an open space topermit natural bone growth when the spacer 102 is disposed in theosteotomy gap 40. During natural bone growth, the natural bone can growand fill at least a portion of the opening 168 when the spacer 102 isdisposed in the osteotomy gap 40.

The spacer 102 further defines a first slot 170 that extend through thespacer body 148 from the first lateral end 156 to the second lateral end158. Hence, the first slot 170 can be elongate along the lateraldirection 160. The first slot 170 is located closer to the firstlongitudinal end 152 than to the second longitudinal end 154, and isconfigured and sized to receive at least a portion of the spacerfixation member 128 so as to couple the spacer 102 to the spacerfixation member 128. In the depicted embodiment, the first slot 170 candefine a plane that is substantially normal to the longitudinaldirection 150. The intermediate fixation member 142 can have asubstantially planar configuration so that it is configured to fitwithin the slot 170 of the spacer 102, thereby coupling the spacer 102to the spacer fixation member 128.

In addition to the first slot 170, the spacer 102 includes at least onesecond slot 172 that extends through the spacer body 148 from the firstlateral end 156 to the second lateral end 158. In the depictedembodiment, the spacer 102 defines a plurality of second slots 172 thatare spaced from each other along the longitudinal direction 150. Atleast one of the second slots 172 is located closer to the secondlongitudinal end 154 than to the first longitudinal end 152. Each of thesecond slots 172 defines a plane that is oriented at an oblique anglerelative to the longitudinal direction 150. In use, the second slots 172configured to receive bone graft or any other natural or syntheticmaterial capable of promoting bone growth. The second slots 172 do notnecessarily have to be filled with a bone graft or any other bone growthagent. Rather, the second slots 172 provide an open space to permitnatural bone growth when the spacer 102 is disposed in the osteotomy gap40.

During natural bone growth, the natural bone can grow and fill at leasta portion of the second slots 172 when the spacer 102 is disposed in theosteotomy gap 40. The second slots 172 also facilitate cutting thespacer 102. As discussed in detail below, the spacer 102 can be cut todecrease its length 174, which is defined by the distance between thefirst longitudinal end 152 and the second longitudinal end 154 along thelongitudinal direction 150. In operation, the length 174 of the spacer102 may have to be shortened so that the spacer 102 can properly fit inthe osteotomy gap 40. For this purpose, each of the second slots 172 canbe configured and sized to receive at least a portion of a cutting tool,such as a saw. In operation, the saw can be inserted through one of theslots 172 to cut the spacer 102, thereby shortening its length 174. Thespacer 102 can also be partly or entirely made of a material that can becut with a cutting tool such as a saw. The spacer 102 can also include aplurality of tines 173. At least some of the tines 173 are disposedbetween two slots 172. The tines 173 can have a substantially planerconfiguration. In the depicted embodiment, the tines 173 are obliquelyangle relative to the longitudinal direction 150. The spacer 102 can bepartly or entirely made of any suitable biocompatible material such aspolyetheretherketone (PEEK).

With reference to FIGS. 4F-L, the TTA system 100 can be part of a kitthat includes spacers of different sizes. Thus, the kit may includespacers with different lengths, heights, and width. For example, the kitmay include spacers 102 a, 102 b, 102 c, 102 d, 102 e, 102 f, and 102 g.Except for their dimensions, the spacers 102 a, 102 b, 102 c, 102 d, and102 e are substantially similar to the spacer 102 described above withrespect to FIGS. 4A-E. Thus, the spacers 102 g and 102 f aresubstantially similar to the spacer 102 described above with respect toFIGS. 4A-E; however, due to size restrictions, spacers 102 g and 102 fdo not include an opening like the opening 168 of the spacer 102.Moreover, the spacers 102 g and 102 f are smaller than the spacer 102described above with respect to FIGS. 4A-E.

With reference to FIG. 5A, the spacer fixation member 128 is configuredto couple the spacer 102 to the tibial body 23 and the advancetuberosity 30 in order to secure the spacer 102 in the osteotomy gap 40.In the depicted embodiment, the spacer fixation member 128 can beconfigured as the bone plate 130, and includes a body 134 thatconfigured and sized to partially fit within the first slot 170 of thespacer 102. The body 134 can also be referred to as the plate body.Furthermore, the body 134 can define the first end portion 138, thesecond end portion 140, and the intermediate fixation portion 142disposed between the first end portion 138 and the second end portion140.

The first end portion 138 can be elongate along a longitudinal axis 176,and can configured to be attached to the advanced tuberosity 30. Tofacilitate attachment between the spacer fixation member 128 and theadvanced tuberosity 30, the first end portion 138 can be contoured andconfigured to conform to a lateral surface or a medial surface of theadvanced tuberosity 30, and can include one or more attachment locationssuch as fastener holes 132. The fastener holes 132 can be configured andsized to receive the fastener 136 as discussed above. In the depictedembodiment, the first end portion 138 defines a plurality of fastenerholes 132. The plurality of fastener holes 132 allows a user to attachthe spacer fixation member 128 to the advanced tuberosity 30 atdifferent attachment locations along the first end portion 138. It iscontemplated, however, that the first end portion 138 may define onlyone fastener hole 132.

The intermediate fixation portion 142 can be elongate along thelongitudinal axis 176 and can define at least one fastener hole 178 thatis configured to receive a fastener such as a bone anchor. If necessary,the spacer fixation member 128 can be cut to shorten it, and a fastenercan be inserted through the fasteners hole 178 and into the tibial body23 to couple the spacer fixation member 128 to the tibial body 23. Asdiscussed above, at least part of the intermediate fixation portion 142can configured to be inserted in the first slot 170 so as to couple thespacer fixation member 128 to the spacer 102.

The second end portion 140 can be elongate along a longitudinal axis 178that is angularly offset relative to the longitudinal axis 176. In anembodiment, the second end portion 140 can be contoured and configuredto conform to a lateral or medial surface of the tibial body 23. Tofacilitate attachment between the spacer fixation member 128 and thetibial body 23, the second end portion 140 can include one or moreattachment locations such as the fastener hole 144. In the depictedembodiment, the second end portion 140 define only one fastener hole144. However, the second end portion 140 may include more than onefastener hole 144. As discussed above, a fastener can be insertedthrough the fastener hole 144 and into the tibial body 23 to couple thespacer fixation member 128 to the tibial body 23.

With reference to FIG. 5B, another embodiment of the spacer fixationmember 128 a is substantially similar to the spacer fixation member 128described above with respect to FIG. 5A. However, in this embodiment,the second end portion 140 a includes a first section 141 a that isconnected to the intermediate fixation portion 142 a and elongate alonga longitudinal axis 177 a. The longitudinal axis 177 a may besubstantially perpendicular to the longitudinal axis 176 a. The secondend portion 140 a further includes a second section 143 a that iselongated along a longitudinal axis 179 a. The longitudinal axis 179 amay be angularly offset relative to the longitudinal axis 177 a and thelongitudinal axis 176 a. In operation, the second end portion 140 a ofthe spacer fixation member 128 a can be contoured and configured toconform to a lateral surface or a medial surface of the tibial body 23to facilitate the connection of the spacer fixation member 128 a to thatlateral or medial surface.

With reference to FIGS. 6A-6C, a spacer 202 in accordance with anotherembodiment can be positioned in the osteotomy gap 40 to maintain thetuberosity 30 in the advanced position relative to the tibial body 23.The spacer 202 can include a spacer body 248 that can be partly orentirely made of a polyetheretherketone (PEEK) or any other suitablematerial. The spacer body 248 defines an upper surface 203 and anopposed lower surface 205. The upper surface 203 is spaced from thelower surface along a transverse direction 262. The spacer body 248 caninclude a front surface 207 and an opposed rear surface 209. The rearsurface 209 can be spaced from the front surface 207 along alongitudinal direction 250. The spacer body 248 can define first lateralsurface 211 and a second lateral surface 213. The second lateral surface213 can be spaced from the first lateral surface 211 along a lateraldirection 260.

The spacer 202 further defines a plurality of slots 272 that extend intothe lower surface of the spacer body 248. The slots 272 can be spacedapart from one another along the lateral direction 260. Each of theslots 272 can be elongate along the transverse direction 262. Moreover,each of the slots 272 can extend through the spacer body 248 from thefront surface 207 to the rear surface 209. When the spacer 202 isdisposed in the osteotomy gap 40, the slots 272 provide an open space topermit bone growth. The slots 272 also facilitate cutting of the spacer202 in order to shorten its length. In addition, any suitable natural orsynthetic bone growth material can be disposed in the slots 272 topromote bone growth when the spacer 202 is disposed in the osteotomy gap40. The slots 272 also facilitate cutting of the spacer 202. Asdiscussed above, the spacer 202 may be cut if necessary to properly fitin the osteotomy gap 40. For instance, a cutting tool can be insertedthrough one of the slots 272 to cut the spacer 202, thereby shorteningthe spacer 202 along the lateral direction 260.

The spacer body 248 can include a plurality of resilient tines 275 thatare spaced from one another along the lateral direction 260. Eachresilient tine 275 is disposed between two slots 272. The resilienttines 275 allows the spacer body 248 to be compressed along the lateraldirection 260 when the spacer 202 is disposed in the osteotomy gap 40 soas to allow at least a portion of the spacer body 248 to conform to theshape of the osteotomy gap 40. The resilient tines 275 may also havedifferent lengths so as to define an arch-shaped bottom lower surface205. In particular, the resilient tines 275 may define a concave lowersurface 205 that allows the tines 275 to be compressed against oneanother so as to conform to the shape of the osteotomy gap 40 when thespacer 202 is disposed in the osteotomy gap 40.

The spacer 202 can further include one or more holes 270 that into thespacer body 248 along the lateral direction 260. In the depictedembodiment, the holes 270 extend through the spacer body 248 from thefirst lateral surface 211 to the second lateral surface 213 along thelateral direction 260. When the spacer 202 is disposed in the osteotomygap 40, the holes 270 provide an open space to promote bone growth. Inaddition to the holes 270, the spacer 202 may define one or more ridges273 that extend into the upper surface 203. In the depicted embodiment,the ridges 273 can be spaced from one another along the lateraldirection 260. The ridges 273 can be elongate along the longitudinaldirection 250. In operation, the cutting tool, such as a saw, can beinserted in one of the ridges 273 to cut the spacer 202. Thus, theridges 273 facilitate cutting of the spacer 202. The ridges 273 alsopermit the spacer 202 to flex.

The spacer 202 can further define at least one fastener hole 215 that isconfigured and sized to receive a fastener 133. The fastener 133 can beconfigured to couple the spacer fixation member 128 a (or any otherspacer fixation member) to the spacer 202. In the depicted embodiment,the fastener 133 is configured as a screw, and the fastener hole 215 canbe a threaded hole. It is envisioned, however, that the fastener 133 canbe configured as a nail, a pin, or any other apparatus configured tocouple the spacer fixation member 128 a to the spacer 202. To couple thespacer fixation member 128 a to the spacer 202, the fastener 133 can beinserted through one of the fastener holes 132 a of the spacer fixationmember 128 a and into the fastener hole 215. As discussed above, thespacer fixation member 128 a can also be coupled to the advancedtuberosity 30 and the tibial body 23 via fasteners.

With reference to FIGS. 7A-B, a spacer 302 in accordance with anotherembodiment can be positioned in the osteotomy gap 40 to maintain thetuberosity 30 in the advanced position relative to the tibial body 23.The spacer 302 is substantially similar to the spacer 202. However, inthis embodiment, the resilient tines 375 have substantially similar oridentical lengths and, therefore, do not define a concave lower surface305. Instead, the lower surface 205 may have a substantially planarconfiguration. Moreover, the spacer 302 can further define recesses 371,such as partial holes, that extend into the lower surface 305. Therecesses 371 can be spaced from one another along the longitudinaldirection 350. In operation, the recesses 371 provide an open space topermit bone growth when the spacer 302 is disposed in the osteotomy gap40.

With reference to FIGS. 8A-C, the TTA system 100 can also include a TTAadvancement assembly 400 configured to guide the advancement of thetuberosity 30 relative to the tibial body 23. As discussed in detailbelow, the advancement assembly 400 can be used to advance thetuberosity 30 relative to the tibial body 23 is described in detailbelow. The advancement assembly 400 includes an advancement member 402that is configured to be coupled to the implant 104, which in turn iscoupled to the tuberosity 30. Specifically, the advancement member 402can be coupled to the proximal end portion 112 of the implant 104. Inthe depicted embodiment, the advancement member 402 can be coupled tothe implant 104 at the attachment location defined by the fastener hole118 a. The implant 104 can be attached to the tuberosity 30 and theadvancement member 402. Therefore, the advancement member 402 can bemanipulated to advance the tuberosity 30 (via implant 104) relative tothe tibial body 23.

With continuing reference to FIGS. 8A-C, the advancement member 402 canbe configured as a jig 403, and can include an advancement body 404. Theadvancement body 404 can be configured as a jig body or a frame.Regardless of its configuration, the advancement body 404 defines anattachment location such as a displacement scale hole 406 that isconfigured to securely receive a displacement scale 408. Thus, theadvancement assembly 400 can include a displacement scale 408 that canbe used to measure the longitudinal displacement of the tuberosity 30relative to the tibial body 23. The displacement scale 408 can beremovably attached to the advancement body 404 via the displacementscale hole 408.

The displacement scale 408 includes a body 410 that includes measurementmarkings 412 that can be used to measure the longitudinal displacementof the tuberosity 30 relative to the tibial body 23. In addition to thebody 410, the displacement scale 408 includes a connection member 414that protrudes from the body 410. The connection member 414 can beconfigured as a substantially cylindrical body, and can be removablydisposed in the displacement scale hole 406. The connection member 414can include a connection body 416 and a ring 418 disposed around theconnection body 416. The connection body 416 is configured and sized tobe at least partially received in the displacement scale hole 406. Whenthe connection member 414 is at least partially disposed in thedisplacement scale hole 406, the ring 418 abuts the inner surface of theadvancement body 404 that defines the displacement scale hole 406,thereby establishing a friction fit connection between the connectionmember 414 and the advancement body 404.

The advancement assembly 400 can further include a longitudinaldistraction mechanism 419 that is configured to move the tuberosity 30relative to the tibial body 23 when the advancement assembly 400 iscoupled to the tuberosity 30 and the tibial body 23. In the depictedembodiment, the distraction mechanism 419 can include a distraction arm420 that is movably coupled to the advancement body 404, and an actuator424 such as a knob 426. In operation, the distraction arm 420 isconfigured to move relative to the advancement body 404 upon actuationof the actuator 424. Thus, the actuation of the actuator 424 causes thedistraction arm 420 to move relative to the advancement body 404 along alongitudinal distraction axis 422. In operation, the movement of thedistraction arm 420 relative to the advancement body 404 causes thetuberosity 30 to move relative to the tibial body 23 when theadvancement assembly 400 is coupled to the to the tuberosity 30 and thetibial body 23.

As discussed above, the actuator 424 can be configured as a knob 426.The knob 426 can include a knob body 428, and can define a threaded hole430 that is configured and sized to receive at least a portion of thedistraction arm 420. The threaded hole 430 can extend through the knobbody 428. The distraction arm 420 can include external threads 432 thatare configured to mate with the inner threads disposed around thethreaded hole 430 such that rotation of the knob 426 about thedistraction arm 420 causes the distraction arm 420 to move relative tothe knob 426 along the longitudinal distraction axis 422. Hence, thedistraction arm 420 can be configured to move relative to theadvancement body 404 upon rotation of the knob 426. While thedistraction arm 420 can move longitudinally relative to the advancementbody 404, the knob 426 is fixed longitudinally with respect to theadvancement body 404.

The advancement member 402 can include a first attachment prong 436 anda second attachment prong 438 that are spaced apart from each other soas to define a knob channel 434. The first attachment prong 436 and thesecond attachment prong 438 can protrude from the advancement body 404.The knob channel 434 can be configured and sized to receive the knob 426so as to longitudinally fixe the knob 426 to the advancement member 402while allowing the knob 426 to rotate within the knob channel 434. Theknob 426 can be configured to rotate about the longitudinal distractionaxis 422. The first attachment prong 436 defines a distraction arm hole440 that is configured to receive at least a portion of the distractionarm 420. The distraction arm 402 can slide through the distraction armhole 440. The second attachment prong 438 can define a distraction armchannel 442 that is configured and sized to receive at least a portionof the distraction arm 420. The distraction arm 420 can slide throughthe distraction arm channel 442. The second prong 438 can also define afirst stop member 444 that is configured to abut a second stop member446 of the distraction arm 420 so as to limit the longitudinal movementof the distraction arm 420 relative to the advancement member 402.

The distraction arm 420 can define a first end 448 and a second end 450,the second end 450, as shown in the illustrated embodiment, can in turndefine the second stop member 446. The first end 448 can be spaced fromthe second end 450 along the longitudinal distraction axis 422. Thedistraction arm 420 can further define a dill guide hole 452 thatextends through the second end 450 of the distraction arm 420. The drillguide hole 452 can be configured and sized to receive a drill guide 454,which can be configured as a sleeve. The drill guide 454 can include adrill guide body 456 that defines a first end 460 and a second end 462spaced apart from each other.

The second end 462 can define a threaded tip 464 that is configured andsized to mate with the threaded fastener hole 118 a (FIG. 3) of theimplant 404 so as to couple the drill guide 454 to the implant 104. Thethreaded tip 464 can have a frusto-conical shape. The drill guide 454can define a drill guide opening 458 that extends through the drillguide body 456 between the first end 460 and the second end 462. Thedrill guide opening 458 can be configured and sized to receive a drillbit or a temporary fixation member such as a wire 466. The wire 466 canbe a Kirschner wire, and is configured to be inserted through the drillguide opening 458 and into the tuberosity 30 so as to couple theadvancement assembly 400 to the tuberosity 30 when the drill guide 454is coupled to the distraction arm 420.

The advancement assembly 400 can further include an angular adjustmentmechanism 468 that is configured to adjust the angular position of thetuberosity 30 with respect to the tibial body 23 when the advancementassembly 400 is coupled to the tibial body 23 and the tuberosity 30. Inthe depicted embodiment, the angular adjustment mechanism 468 caninclude an angular adjustment member 470 that is movably coupled to theadvancement body 404. Specifically, the angular adjustment member 470 isconfigured to rotate about an attachment location defined along a pivotaxis R. In particular, the advancement member 402 defines an attachmentlocation such as a hole 472. The hole 472 extends through theadvancement body 404 along the pivot axis R, and is configured toreceive at least a portion of a rotational actuator 474 such that therotational actuator 474 is configured to rotate about the pivot axis Rwithin the hole 472.

The rotational actuator 474 can be configured as a knob 473, andincludes an attachment member 476 that is configured to mate with anattachment member 480 of the angular adjustment member 470 so as tocouple rotational actuator 474 to the angular adjustment member 470. Theattachment member 476 can be configured as an externally threaded body478, and the attachment member 480 can be configured as a threaded hole482. The threaded hole 482 can be configured to mate with the externallythreaded body 478 so as to couple the rotational actuator 474 to theangular adjustment member 470. The angular adjustment member 470 can beconfigured as an angular scale.

The angular adjustment member 470 can also be angularly fixed relativeto the angular body 404 by tightening the rotational actuator 474. Forexample, the rotation of the rotational actuator 474 about the pivotaxis R in a first direction tightens the externally threaded body 478 inthe threaded hole 482, thereby angularly fixing the angular adjustmentmember 470 with respect to the advancement body 404. Conversely, therotation of the rotational actuator 474 in a second direction (oppositeto the first direction) about the pivot axis R loosens the externallythreaded body 478 disposed in the threaded hole 482, thereby allowingthe angular adjustment member 470 to rotate about the pivot axis R withrespect to the advancement body 404.

The angular adjustment member 470 includes an angular scale body 484that is elongate along a longitudinal direction 486. The angular scalebody 484 can have a substantially planar configuration, and defines afirst scale end 488 and a second scale end 490. The second scale end 490is spaced from the first scale end 488 along the longitudinal direction486. The threaded hole 482 can be located at or close to the first scaleend 488. The angular adjustment member 470 can further include a contactmember 494 that protrudes from angular scale body 484 along a lateraldirection 492. The lateral direction 492 can be substantiallyperpendicular to the longitudinal direction 486. The contact member 494can have a substantially planar configuration, and is configured andsized to be disposed in the osteotomy gap 40. The contact member 494 canbe a brace, a blade or any apparatus suitable to contact the tibialtuberosity 30, the tibial body 23, or both, when positioned in theosteotomy gap 40.

The angular adjustment member 470 can further include angular markings491 disposed along the second scale end 490. The angular markings 491help users determine the angular orientation of the contact member 494relative to the advancement body 404. In particular, the angularmarkings 491 are disposed along an arc, which center is defined by theattachment member 480. The angular adjustment member 470 furtherincludes a plurality of openings or recesses 496 disposed adjacent theangular markings 491. The openings 496 spaced from one another along anarc, which center is defined by the attachment member 480. Each of theopenings 496 is configured and sized to receive a post 498 thatprotrudes from the advancement body 404 in the lateral direction 492.The engagement between the post 498 and each of the openings 496 allowsa user to adjust the angular orientation of the angular adjustmentmember 470 at predetermined increments.

The angular adjustment member 470 further defines an arc-shaped opening499 that extends through the angular scale body 484 along the lateraldirection 492. The arc-shaped opening 499 can be elongate along an arc,which center is defined by the attachment member 480. In the depictedembodiment, the arc-shaped opening 499 is configured and sized toreceive a temporary fixation member such as a wire 497. The wire 497 canbe a Kirschner wire, and is configured to be inserted through thearc-shaped opening 499, an opening 495 of the advancement member 402,and into a portion of the tibial body 23, such as the tibial diaphysis,so as to couple the advancement assembly 400 to the tibial body 23. Asdiscussed above, the advancement member 402 defines an opening 495 thatextends through the advancement body 404 in the lateral direction 492.The opening 495 is substantially aligned with the arc-shaped opening499, and can be configured and sized to receive the wire 497. Whileusing the TTA system 100, the user, such as a surgeon, may observe itsactions along a viewing direction 72. Thus, the user's line of sightwhen using the TTA system 100 extends along the viewing direction 72.

With reference to FIG. 9, the conventional common tangent method can beused to determine longitudinal and angular advancement of the tuberosity30 relative to the tibial body 23. The common tangent method can beperformed by a processor in a computer. Alternatively, the commontangent method can be performed by placing transparent overlays over anx-ray film. An example of the common tangent method includes all or someof the following steps. First, a first circle 502 is drawn around thearticulating surface of the femur 24. A second circle 504 is drawnaround the articulating surface of the tibia 22.

The first and second circles 502 and 504 should touch, for example suchthat the first and second circles 502 and 504 are tangent to each other.Then, a line 506 is drawn connecting the center 508 of the first circle502 and the center 510 of the second circle 504. Next, a common tangentline CTL is drawn. The line CTL is tangential to the first circle 502and the second circle 504 and perpendicular to the line 506. The lineCTL represents the slope of the tibial plateau 28 and the direction ofthe cranial tibial thrust.

Next, the length of the patellar tendon 32 (shown in FIG. 1) ismeasured. The length of the patellar tendon 32 is defined between thedistal pole P of the patella 511 wherein the patellar tendon 32originates and the location in the tuberosity 30 where the patellartendon 32 is inserted. The location where the patellar tendon 32 insertsinto the tuberosity 30 is referred to in the present disclosure as theinsertion point I. The length of the patellar tendon 32 can then berecorded as distance PI. Then, a line 512 is drawn from the distal poleP of the patella 511 to determine the target point T. The line 512 isperpendicular to the line CTL and has a length that is equal to thedistance PI. The target point T is the desired location of thetuberosity 30 after the TTA procedure has been performed. That is, whenthe tibial tuberosity 30 is fixed at the target point T, thetibiofemoral sheer force is neutralized when weight is applied to theknee joint 20, thereby reducing or altogether bypassing the anatomicalfunction of the CCL.

Next, the osteotomy line 514 is identified. The osteotomy line 514 canbe disposed between the Gerdy's Tubercle (i.e., the lateral tubercle ofthe tibia) to the distal aspect of the tibial tuberosity 30. Thedistance D1 from the insertion point I to the most proximal end of theosteotomy line 514 is measured. A distance D2 from the insertion point Ito most distal end of the osteotomy line 514 is measured. Next, a lineTI is drawn from the target point T to the insertion point I. The lineTI can then be extended to the osteotomy line 514. The advancementdistance AD from the target point T to the insertion point I ismeasured. Then, the advancement angle AA is determined by measuring theacute angle between the line TI and the osteotomy line 514.

Next, in a computer, the virtual model of the implant 104 is placed overthe virtual representation of the tibia 22 and femur 24 to determine thecorrect size of the implant 104. Alternatively, the size of the implant104 can be determined by placing an overlay that represents the implant104 over a radiograph of the tibia 22 and the femur 24. In this process,the proximal end portion 112 of the implant 104 should be parallel tothe cranial edge of the tuberosity. Also, in this process, the fastenerhole 118 a should be placed at a predetermined distance (e.g., fromabout 1 to 2 millimeters) caudal to the insertion point I along the lineTI. The steps described above can be defined as a pre-operative plan.

Upon completion of the pre-operative plan, the osteotomy may beperformed. In particular, the osteotomy can be conducted from the distalaspect of the tibial tuberosity in accordance with the pre-operativeplan described above. The osteotomy can be made with any suitablecutting tool. However, the osteotomy is stopped at a predetermineddistance (e.g., about 3 to 4 millimeters) from the proximal cortex ofthe tibial tuberosity 30.

Referring to FIGS. 8A-9, after partially performing the osteotomy, thedrill guide 454 is at least partially inserted through the dill guidehole 452. Then, the second end 462 of the drill guide 452 is secured inthe fastener hole 118 a of the implant 104 as described in detail above.The angular adjustment member 470 is then rotated relative to theadvancement body 404 such that the post 498 is aligned with the markingthat is equal to the predetermined advancement angle AA. The angularadjustment member 470 is then fixed relative to the advancement body 404by tightening the rotational actuator 474 in the threaded hole 482 asdescribed above.

The contact member 494 is inserted in the osteotomy, and then the bladeis moved further into the osteotomy until the distraction arm 420 isdisposed over the insertion point I as determined in the pre-operativeplanning. The wire 466 is then inserted through the drill guide 454 andthe fastener hole 118 a, and into tibial tuberosity 30 in order tosecure the advancement assembly 400 and the implant 104 to the tibialtuberosity 30. The wire 466 should be oriented in the lateral direction492. Next, the wire 497 can be inserted through the opening 495 and thearc-shaped opening 499 and into a portion of the tibial body 23, such asthe tibial diaphysis, in order to secure the advancement assembly 400 tothe tibial body 23. The actuator 424 is actuated to move distraction arm420 toward the tibial body 23 in order to compress the osteotomy until alight resistance is felt. The distraction arm 420 can be moved towardthe tibial body 23 by turning the knob 426 in a first direction. At thispoint, the user should record the starting point of the distraction arm420 by noting the location of the first end 448 of the distraction arm420 in relation to the markings 412 of the displacement scale 408. Theimplant 104 is then aligned with the cranial aspect of the tibialtuberosity 30 as determined in the pre-operative plan, and the fastenercan be inserted in at least one of the fastener holes 118 b, 118 c, or118 d, to prevent rotation of the implant 104.

Alternatively, the advancement assembly 400 and the implant 104 can becoupled to the tibial tuberosity 30 and the tibial body 23 by performingthe following steps. First, a first drill guide, which can be identicalto the drill guide 454, is at least partially inserted in the fastenerhole 118 a so as to couple the drill guide 454 to the implant 104. Theimplant 104 is then placed on the tibial tuberosity 30 in accordancewith the pre-operative plan. Then, the wire 466 is inserted through thedrill guide 454 and into the tibial tuberosity 30, while leaving thefirst drill guide 454 coupled to the implant 104 and holding the implant104 against the tibial tuberosity 30. The implant 104 is rotated so thatthe proximal end portion 112 of the implant 104 is substantiallyparallel to the cranial edge of the tuberosity.

A second drill guide, which can be identical to the drill guide 454, isthen inserted through the fastener hole 118 d so as to couple the seconddrill guide to the implant 104 at the fastener hole 118 d. A drill bitcan be inserted through the second drill guide and the fastener hole 118d to drill hole into the tibial tuberosity 30. A fastener, such as alocking screw, is then inserted in to the drilled hole in the tibialtuberosity 30. The angular adjustment member 470 is then adjusted at theadvancement angle AA as predetermined in the pre-operative plan. Theknob 473 is then tightened to fix the angular orientation of the angularadjustment member 470 with respect to the advancement body 404. Thefirst drill guide is then decoupled from the implant 104 and withdrawnfrom the animal. Then, the advancement member 404 is advanced over thewire 466 such that the wire 466 is disposed in the drill guide hole 452.The distraction arm 420 can be moved away from the tibial body 23 sothat the contact member 494 can be inserted in the osteotomy. Thecontact member 494 is then inserted in the osteotomy. Next, the wire 497can be inserted through the opening 495 and the arc-shaped opening 499and into a portion of the tibial body 23 such as the tibial diaphysis.

After coupling the advancement assembly 400 and the implant 104 to thetibial tuberosity 30 and the tibial body 123, the osteotomy can becompleted by cutting all the way through the proximal cortex of thetibial tuberosity 30. The distraction arm 420 is then moved (via theactuator 424) away from the tibial body 23 a distance equal to theadvancement distance AD. The displacement scale 408 can be used tomeasure the displacement of the distraction arm 420. To this end, theuser can gradually turn the knob 426 in a second direction until thefirst end 448 of the distraction arm 420 moves a distance that issubstantially equal to the advancement distance AD as measured by themarkings 412. Thus, the translation of the distraction arm 420 apredetermined distance (i.e., advancement distance AD) causes theadvancement assembly 400 (for example the displacement scale 408) toprovide an indication that the tuberosity has advanced from the firstposition to the advanced position.

Then, the tibial tuberosity 30 is rotated relative to the tibial body 23until its distal end 31 contact a surface 25 of the tibial body 23 thatdefines a distal end of osteotomy seen in FIG. 9. The fasteners 124 arethen inserted through the fastener holes 122 a and 122 b and into thetibial body 23 to couple the distal end portion 114 of the implant 104to the tibial body 23. The osteotomy gap 40 is then measured todetermine the appropriate spacer size and spacer fixation member size.The spacer fixation member 128 is then coupled to the spacer 102 asdescribed above.

Then, the spacer 102 is then inserted in the osteotomy gap 40 to verifythat the appropriate size was selected. The advancement assembly 400 maybe withdrawn from the animal to expand the working space. If the properspacer 102 was selected, the spacer 102 is cut (if necessary) so that itconforms to the size of the osteotomy gap 40. The spacer 102 and thespacer fixation member 128 can then be secured in the osteotomy gap 40by inserting the fastener 136 through the fastener holes 132 and intothe tibial tuberosity 30 and by inserting another fastener 136 throughthe fastener holes 144 and into the tibial body 23. If the advancementassembly 400 has not been removed from the animal yet, the advancementassembly 400 can be decoupled from the tibial tuberosity 30 and thetibial body 23 and removed from the animal.

The advancement assembly 400 can be decoupled from the tibial tuberosity30 and the tibial body 23 by removing the wires 466 and 497 from thetibial tuberosity 30 and the tibial body 23, respectively. Oncedecoupled, the advancement assembly 400 can be removed from the animal.A drill bit can be inserted through the fastener hole 118 a to create adrill hole that is appropriate for the fastener 120. Then, the fastener120 can be inserted through the fastener hole 118 a and into the tibialtuberosity 30 to secure the implant 104 to the tibial tuberosity 30.Additional fasteners 120 can be inserted through the fasteners holes 118b, 118 c, and 118 d and into tibial tuberosity 30 as deemed necessaryfor a secure connection between the implant 104 and the tibialtuberosity 30.

Referring to FIGS. 3 and 10A-10I, in another embodiment, the TTA system100 can include an alternate embodiment of the implant 104 (shown inFIG. 3), such as implant 604 (shown in FIGS. 10A-10H). The implant 604can be constructed as a bone fixation member 606, such as a bone plate608. In the depicted embodiment, the implant 604 includes an implantbody 610 that includes a proximal end portion 612, an opposed distal endportion 614, and an intermediate implant portion 616 disposed betweenthe proximal end portion 612 and the distal end portion 614. Theproximal end portion 612 of the implant body 610 can be configured to beattached to the tuberosity 30 that has been advanced along with thepatellar tendon 32 (shown in FIG. 1) in a direction cranially relativeto the tibial body 23 from a first position to an advanced position. Thedistal end portion 614 of the implant body 610 can be configured to beattached to the tibial body 23.

It should be appreciated that the patellar tendon 32 is attached to thetuberosity 30 at an anatomical attachment location 43, and that thetuberosity 30 can be resected, and thus separated, from the tibial body23 at a location caudal of the attachment location 43 such that thepatellar tendon 32, including the attachment location 43, is advancedalong with the separated tuberosity 30 from the first position to theadvanced position. The proximal end portion 612, the distal end portion614, and the intermediate implant portion 616 can collectively be amonolithic structure. Alternatively, proximal end portion 612, thedistal end portion 614, and the intermediate implant portion 616 can bediscrete components that are connected to each other to form the implantbody 610.

The proximal end portion 612 can be contoured and configured to conformto a medial surface or lateral surface of the tuberosity 30 tofacilitate attachment of the implant 604 to the tuberosity 30. Moreover,the proximal end portion 612 includes one or more attachment locationssuch as fastener holes. In the depicted embodiment, the proximal endportion 612 of the implant body 610 includes four fastener holes 618 a,618 b, 618 c, and 618 d. However, the proximal end portion 612 mayinclude more or fewer fastener holes. Each fastener hole 618 a, 618 b,618 c, and 618 d extends through the implant body 610, and is configuredand sized to receive a fastener 120, such as a bone anchor, that iscapable of attaching the implant 604 to the tuberosity 30. The fastenerholes 618 a, 618 b, 618 c, and 618 d can be threaded holes that areconfigured to receive a bone screw. In another embodiment the fastenersholes 618 a, 618 b, 618 c, and 618 d can be conical thread holes thatare configured receive bone screws with a threaded or non-threadedconical head.

The insertion of fasteners 120 through fastener holes 618 a, 618 b, 618c, and 618 d causes the proximal end portion 612 to be attached to thetuberosity 30. The fastener holes 618 a, 618 b, 618 c, and 618 d may bespaced apart from one another and substantially aligned along a firstlongitudinal axis L1′ that extends substantially parallel to thedirection of elongation of the tuberosity 30 when the implant 604 isattached to the advanced tuberosity 30. In one embodiment the proximalend portion 112 can be elongate along the longitudinal axis L1′.

The distal end portion 614 can be contoured and configured to conform toa medial surface or a lateral surface of the tibial body 23 tofacilitate attachment of the implant 604 to the tibial body 23. Further,the distal end portion 614 of the implant body 610 can include one ormore anchor locations such as fastener holes. In the illustratedembodiment, the distal end portion 614 includes fastener holes 622 a,622 b, 622 c, and 622 d. Each of the fastener holes 622 a, 622 b, 622 c,and 622 d can be configured and sized to receive a fastener 124, such asa bone anchor, capable of attaching the implant 604 to the tibial body23.

The insertion of fasteners 124 through the fastener holes 622 a, 622 b,622 c and 622 d causes the distal end portion 614 to be attached to thetibial body 23. The fastener holes 622 a, 622 b, 622 c, and 622 d may bespaced apart from one another and substantially aligned along a secondlongitudinal axis L2′. In one embodiment the distal end portion 614 canbe elongate along the second longitudinal axis L2′. The firstlongitudinal axis L1′ may be angularly offset from the secondlongitudinal axis L2′ such that an offset angle OA is defined. The firstand second longitudinal axes L1′ and L2′ can be offset such that offsetangle OA is between about 170 degrees and about 130 degrees. In anotherembodiment the first and second longitudinal axes L1′ and L2′ can beoffset such that offset angle OA is about 150 degrees. In anotherembodiment the offset angle OA is about 180 degrees (or 0 degrees) suchthat the first and second longitudinal axes L1′ and L2′ are parallel ornot angularly offset.

The intermediate implant portion 616 of the implant body 610 can besubstantially curved. Alternatively, the intermediate implant portion616 may be substantially straight and elongated along an axis that iseither angularly offset from or parallel to the second longitudinal axisL2′. Although the drawings do not show attachment locations, such asfastener holes, in the intermediate implant portion 616, it isenvisioned that the intermediate implant portion 616 may include one ormore fastener holes or any other suitable attachment feature. Theintermediate implant portion 616 extends between the proximal endportion 612 and the distal end portion 614 and is shaped so as to spacethe proximal end portion 612 cranially with respect to the distal endportion 614 an amount, or a distance, sufficient so as to maintain thetuberosity 30 in the advanced position.

The implant body 610 can further define a first surface 626 and a secondsurface 628 that is opposite the first surface 626. In one embodiment,the first surface 626 is configured to face a tibial body 23 and atuberosity 30 of a tibia 22, and the second surface 628 is configured toface away from the tibial body 23 and the tuberosity 30, when theimplant 604 is implanted adjacent to a tibia 22. In another embodiment,the second surface 628 is configured to face a tibial body 23 and atuberosity 30 of a tibia 22, and the first surface 626 is configured toface away from the tibial body 23 and the tuberosity 30, when theimplant 604 is implanted adjacent to a tibia 22.

The implant body 610 can define a thickness measured between the firstsurface 626 and the second surface 628. In one embodiment, the thicknessof the plate can be constant along the implant body 610, for example asshown in FIG. 3. In another embodiment, the thickness of the implantbody 610 can vary. For example the implant body 610 can define aproximal portion thickness T1, a distal portion thickness T2, and anintermediate portion thickness T3. As stated above, the proximal portionthickness T1, the distal portion thickness T2, and the intermediateportion thickness T3 can all be substantially equal. In anotherembodiment, the proximal portion thickness T1, the distal portionthickness T2, and the intermediate portion thickness T3 can besubstantially unequal. For example, the intermediate implant portion 616can include a thinned out or necked portion 630 that defines anintermediate portion thickness T3 that is less than at least one (oralternatively, both) of the proximal and distal portion thicknesses T1and T2. The necked portion 630 and reduced intermediate portionthickness T3 can allow for the implant 604 to be bent or flexed suchthat first surface 626 corresponds more closely with the surfaces of thetibial body 23 and the tuberosity 30 then if the implant body 610 had aconstant thickness. In another embodiment, each of the proximal portionthickness T1, the distal portion thickness T2, and the intermediateportion thickness T3, can be either greater than, less than, or equal toany of the other portion thicknesses.

In another embodiment the proximal end portion 612, the distal endportion 614, or both can include a thinned out or necked portion 630.The necked portion 630 of any of the proximal end portion 612, thedistal end portion 614, or the intermediate portion 616 may onlycomprise a portion of the respective implant portion such that therespective thickness T1, T2, or T3 varies within that implant portion.The necked portion 630 can include at least one transition 632, forexample two transitions 632, where the thickness of the implant body 610changes. As shown in the illustrated embodiment, the transition 632 canbe a radiused surface 633 resulting in a gradual change in thickness. Inanother embodiment the transition 632 can include a step resulting in asudden change in thickness. In another embodiment, the transition 632can include both a radiused surface 633 and a step surface resulting ina partial gradual change in thickness and a partial sudden change inthickness. In another embodiment the implant body 610 can includetransitions 632 that are different, for example one transition 632 witha radiused surface 633 and another transition 632 with a step surface.

The implant body 610 can include a first side surface 634 and a secondside surface 636 opposite the first side surface 634. The first andsecond side surfaces 634 and 636 can each extend between the firstsurface 626 and the second surface 628 in one direction, and between theproximal end portion 612 and the distal end portion 614 in anotherdirection. The implant body 610 can define a width measured between thefirst side surface 634 and the second side surface 636. In oneembodiment, the width of the plate can be constant along the implantbody 610, for example as shown in FIG. 3. In another embodiment, thewidth of the implant body 610 can vary. For example the implant body 610can define a proximal portion width W1, a distal portion width W2, andan intermediate portion width W3.

As stated above, the proximal portion width W1, the distal portion widthW2, and the intermediate portion width W3 can all be substantiallyequal. In another embodiment, the proximal portion width W1, the distalportion width W2, and the intermediate portion width W3 can besubstantially unequal. For example, the implant body 610 can include aneck 638 between the proximal end portion 612 and the intermediateimplant portion 616, such that the width of the implant body 610 changesalong the neck 638. As shown in the illustrated embodiment, the width ofthe implant body transitions along the neck 638 from the greaterintermediate portion width W3 down to the smaller proximate portionwidth W1. In another embodiment, each of the proximal portion width W1,the distal portion width W2, and the intermediate portion width W3, canbe either greater than, less than, or equal to any of the other portionwidths.

In one embodiment the implant body 610 can include at least onescalloped portion 640. The scalloped portion 640 can include aperipheral side wall 642 and a raised surface 644. In one embodiment theraised surface 644 extends out from the first surface 626 and can beconfigured to face a tibial body 23 and a tuberosity 30 of a tibia 22when the implant 604 is implanted adjacent to a tibia 22. In theillustrated embodiment, the distal end portion 614 includes scallopedportions 640 a, 640 b, 640 c, and 640 d. In one embodiment the scallopedportion 640 can include a partial peripheral side wall 642 d that doesnot completely define the outer boundary of the scalloped portion 640 d.

As shown in the illustrated embodiment, the implant body 610 can includeadjacent scalloped portions 640, for example scalloped portions 640 band 640 c or scalloped portions 640 c and 640 d. The adjacent scallopedportions 640 can be separated by a gap 646 that is defined by the facingportions of the peripheral side walls 642, for example 642 b and 642 c.The gap 646 can extend through an entirety of the width of therespective implant portion (proximal portion width W1, distal portionwidth W2, intermediate portion width W3) that carries the adjacentscalloped portions 640. In an alternative embodiment the gap 646 canextend only partially through the width of the respective implantportion that carries the adjacent scalloped portions 640. The gap 646can vary in size along the width of the implant portion that carries theadjacent scalloped portions 640. For example, as shown in theillustrated embodiment, the gap 646 can be wider at the ends of the gap646 along the width (adjacent the first and second side walls 634 and636) and narrower around the middle of the gap 646 along the width.

The facing portions of the peripheral side walls 642 b and 642 c of theadjacent scalloped portions 640 b and 640 c can include a taperedportion, a substantially parallel portion, or both. In the substantiallyparallel portion the peripheral side walls 642 b and 642 c of theadjacent scalloped portions 640 b and 640 c extend along the widthsubstantially parallel to each other such that the size of the gap 646is substantially constant. In the tapered portion the peripheral sidewalls 642 b and 642 c of the adjacent scalloped portions 640 b and 640 cflare away from each other along the width. As shown in the illustratedembodiment, the peripheral side walls 642 b and 642 c of the adjacentscalloped portions 640 b and 640 c can flare away from each otherlinearly such that a first gap angle 648 is defined. The first gap angle648 can be from about 45 degrees to about 135 degrees, or in anotherembodiment the first gap angle 648 can be about 90 degrees. In anotherembodiment the peripheral side walls 642 b and 642 c of the adjacentscalloped portions 640 b and 640 c can flare away from each othernonlinearly.

In addition to extending along the width of the plate, the gap 646 canextend along the thickness of the plate, for example the gap 646 canextend into the first surface 626 toward the second surface 628. In oneembodiment the peripheral side walls 642 b and 642 c of the adjacentscalloped portions 640 b and 640 c flare away from each other along thethickness of the implant body 610. As shown in the illustratedembodiment, the peripheral side walls 642 b and 642 c of the adjacentscalloped portions 640 b and 640 c can flare away from each otherlinearly such that a second gap angle 650 is defined. The second gapangle 650 can be from about 0 degrees to about 60 degrees, or in anotherembodiment the second gap angle 650 can be about 30 degrees. In anotherembodiment the peripheral side walls 642 b and 642 c of the adjacentscalloped portions 640 b and 640 c can flare away from each othernonlinearly along the thickness.

Referring to FIGS. 3 and 11A-11I, in another embodiment, the TTA system100 can include another embodiment of the implant 104 (shown in FIG. 3),such as implant 704 (shown in FIGS. 11A-11H). The implant 704 can beconstructed as a bone fixation member 706, such as a bone plate 708. Inthe depicted embodiment, the implant 704 includes an implant body 710that includes a proximal end portion 712, an opposed distal end portion714, and an intermediate implant portion 716 disposed between theproximal end portion 712 and the distal end portion 714. The proximalend portion 712 of the implant body 710 can be configured to be attachedto the tuberosity 30 that has been advanced along with the patellartendon 32 (shown in FIG. 1) in a direction cranially relative to thetibial body 23 from a first position to an advanced position. The distalend portion 714 of the implant body 710 can be configured to be attachedto the tibial body 23.

It should be appreciated that the patellar tendon 32 is attached to thetuberosity 30 at an anatomical attachment location 43, and that thetuberosity 30 can be resected, and thus separated, from the tibial body23 at a location caudal of the attachment location 43 such that thepatellar tendon 32, including the attachment location 43, is advancedalong with the separated tuberosity 30 from the first position to theadvanced position. The proximal end portion 712, the distal end portion714, and the intermediate implant portion 716 can collectively be amonolithic structure. Alternatively, proximal end portion 712, thedistal end portion 714, and the intermediate implant portion 716 can bediscrete components that are connected to each other to form the implantbody 710.

The proximal end portion 712 can be contoured and configured to conformto a medial surface or lateral surface of the tuberosity 30 tofacilitate attachment of the implant 704 to the tuberosity 30. Moreover,the proximal end portion 712 includes one or more attachment locationssuch as fastener holes. In the depicted embodiment, the proximal endportion 712 of the implant body 710 includes four fastener holes 718 a,718 b, 718 c, and 718 d. However, the proximal end portion 712 mayinclude more or fewer fastener holes. Each fastener hole 718 a, 718 b,718 c, and 718 d extends through the implant body 710, and is configuredand sized to receive a fastener 120, such as a bone anchor, that iscapable of attaching the implant 704 to the tuberosity 30. The fastenerholes 718 a, 718 b, 718 c, and 718 d can be threaded holes that areconfigured to receive a bone screw. In another embodiment the fastenersholes 718 a, 718 b, 718 c, and 718 d can be conical thread holes thatare configured receive bone screws with a threaded or non-threadedconical head.

The insertion of fasteners 120 through fastener holes 718 a, 718 b, 718c, and 718 d causes the proximal end portion 712 to be attached to thetuberosity 30. The fastener holes 718 a, 718 b, 718 c, and 718 d may bespaced apart from one another and substantially aligned along a firstlongitudinal axis L1″ that extends substantially parallel to thedirection of elongation of the tuberosity 30 when the implant 704 isattached to the advanced tuberosity 30. In one embodiment the proximalend portion 112 can be elongate along the longitudinal axis L1″.

The distal end portion 714 can be contoured and configured to conform toa medial surface or a lateral surface of the tibial body 23 tofacilitate attachment of the implant 704 to the tibial body 23. Further,the distal end portion 714 of the implant body 710 can include one ormore anchor locations such as fastener holes. In the illustratedembodiment, the distal end portion 714 includes fastener holes 722 a,722 b, 722 c, and 722 d. Each of the fastener holes 722 a, 722 b, 722 c,and 722 d can be configured and sized to receive a fastener 124, such asa bone anchor, capable of attaching the implant 704 to the tibial body23.

The insertion of fasteners 124 through the fastener holes 722 a, 722 b,722 c, and 722 d causes the distal end portion 714 to be attached to thetibial body 23. The fastener holes 722 a, 722 b, 722 c, and 722 d may bespaced apart from one another and substantially aligned along a secondlongitudinal axis L2″. In one embodiment the distal end portion 714 canbe elongate along the second longitudinal axis L2″. The firstlongitudinal axis L1″ may be angularly offset from the secondlongitudinal axis L2″ such that an offset angle OA′ is defined. Thefirst and second longitudinal axes L1″ and L2″ can be offset such thatoffset angle OA′ is between about 180 degrees and about 160 degrees. Inanother embodiment the first and second longitudinal axes L1″ and L2″can be offset such that offset angle OA′ is about 170 degrees. Inanother embodiment the offset angle OA′ is 180 degrees (or 0 degrees)such that the first and second longitudinal axes L1″ and L2″ areparallel or not angularly offset.

The intermediate implant portion 716 of the implant body 710 can besubstantially curved. Alternatively, the intermediate implant portion716 may be substantially straight and elongated along an axis that iseither angularly offset from or parallel to the second longitudinal axisL2″. Although the drawings do not show attachment locations, such asfastener holes, in the intermediate implant portion 716, it isenvisioned that the intermediate implant portion 716 may include one ormore fastener holes or any other suitable attachment feature.

The intermediate implant portion 716 extends between the proximal endportion 712 and the distal end portion 714 and is shaped so as to spacethe proximal end portion 712 cranially with respect to the distal endportion 714 an amount, or a distance, sufficient so as to maintain thetuberosity 30 in the advanced position.

The implant body 710 can further define a first surface 726 and a secondsurface 728 that is opposite the first surface 726. In one embodiment,the first surface 726 is configured to face a tibial body 23 and atuberosity 30 of a tibia 22, and the second surface 728 is configured toface away from the tibial body 23 and the tuberosity 30, when theimplant 704 is implanted adjacent to a tibia 22. In another embodiment,the second surface 728 is configured to face a tibial body 23 and atuberosity 30 of a tibia 22, and the first surface 726 is configured toface away from the tibial body 23 and the tuberosity 30, when theimplant 704 is implanted adjacent to a tibia 22.

The implant body 710 can define a thickness measured between the firstsurface 726 and the second surface 728. In one embodiment, the thicknessof the plate can be constant along the implant body 710, for example asshown in FIG. 3. In another embodiment, the thickness of the implantbody 710 can vary. For example the implant body 710 can define aproximal portion thickness T1′, a distal portion thickness T2′, and anintermediate portion thickness T3′. As stated above, the proximalportion thickness T1′, the distal portion thickness T2′, and theintermediate portion thickness T3′ can all be substantially equal. Inanother embodiment, the proximal portion thickness T1′, the distalportion thickness T2′, and the intermediate portion thickness T3′ can besubstantially unequal. For example, the intermediate implant portion 716can include a thinned out or necked portion 730 that defines anintermediate portion thickness T3′ that is less than at least one (oralternatively, both) of the proximal and distal portion thicknesses T1′and T2′. The necked portion 730 and reduced intermediate portionthickness T3′ can allow for the implant 704 to be bent or flexed suchthat first surface 726 corresponds more closely with the surfaces of thetibial body 23 and the tuberosity 30 then if the implant body 710 had aconstant thickness. In another embodiment, each of the proximal portionthickness T1′, the distal portion thickness T2′, and the intermediateportion thickness T3′, can be either greater than, less than, or equalto any of the other portion thicknesses.

In another embodiment the proximal end portion 712, the distal endportion 714, or both can include a thinned out or necked portion 730.The necked portion 730 of any of the proximal end portion 712, thedistal end portion 714, or the intermediate portion 716 may onlycomprise a portion of the respective implant portion such that therespective thickness T1′, T2′, or T3′ varies within that implantportion. The necked portion 730 can include at least one transition 732,for example two transitions 732, where the thickness of the implant body710 changes. As shown in the illustrated embodiment, the transition 732can be a radiused surface 733 resulting in a gradual change inthickness. In another embodiment the transition 732 can include a stepresulting in a sudden change in thickness. In another embodiment, thetransition 732 can include both a radiused surface 733 and a stepsurface resulting in a partial gradual change in thickness and a partialsudden change in thickness. In another embodiment the implant body 710can include transitions 732 that are different, for example onetransition 732 with a radiused surface 733 and another transition 732with a step surface.

The implant body 710 can include a first side surface 734 and a secondside surface 736 opposite the first side surface 734. The first andsecond side surfaces 734 and 736 can each extend between the firstsurface 726 and the second surface 728 in one direction, and between theproximal end portion 712 and the distal end portion 714 in anotherdirection. The implant body 710 can define a width measured between thefirst side surface 734 and the second side surface 736. In oneembodiment, the width of the plate can be constant along the implantbody 710, for example as shown in FIG. 3. In another embodiment, thewidth of the implant body 710 can vary. For example the implant body 710can define a proximal portion width W1′, a distal portion width W2′, andan intermediate portion width W3′.

As stated above, the proximal portion width W1′, the distal portionwidth W2′, and the intermediate portion width W3′ can all besubstantially equal. In another embodiment, the proximal portion widthW1′, the distal portion width W2′, and the intermediate portion widthW3′ can be substantially unequal. For example, the implant body 710 caninclude a neck 738 between the proximal end portion 712 and theintermediate implant portion 716, such that the width of the implantbody 710 changes along the neck 738. As shown in the illustratedembodiment, the width of the implant body transitions along the neck 738from the greater intermediate portion width W3′ down to the smallerproximate portion width W1′. In another embodiment, each of the proximalportion width W1′, the distal portion width W2′, and the intermediateportion width W3′, can be either greater than, less than, or equal toany of the other portion widths.

In one embodiment the implant body 710 can include at least onescalloped portion 740. The scalloped portion 740 can include aperipheral side wall 742 and a raised surface 744. In one embodiment theraised surface 744 extends out from the first surface 726 and can beconfigured to face a tibial body 23 and a tuberosity 30 of a tibia 22when the implant 704 is implanted adjacent to a tibia 22. In theillustrated embodiment, the distal end portion 714 includes scallopedportions 740 a, 740 b, 740 c, and 740 d. In one embodiment the scallopedportion 740 can include a partial peripheral side wall 742 d that doesnot completely define the outer boundary of the scalloped portion 740 d.

As shown in the illustrated embodiment, the implant body 710 can includeadjacent scalloped portions 740, for example scalloped portions 740 band 740 c or scalloped portions 740 c and 740 d. The adjacent scallopedportions 740 can be separated by a gap 746 that is defined by the facingportions of the peripheral side walls 742, for example 742 b and 742 c.The gap 746 can extend through an entirety of the width of therespective implant portion (proximal portion width W1′, distal portionwidth W2′, intermediate portion width W3′) that carries the adjacentscalloped portions 740. In an alternative embodiment the gap 746 canextend only partially through the width of the respective implantportion that carries the adjacent scalloped portions 740. The gap 746can vary in size along the width of the implant portion that carries theadjacent scalloped portions 740. For example, as shown in theillustrated embodiment, the gap 746 can be wider at the ends of the gap746 along the width (adjacent the first and second side walls 734 and736) and narrower around the middle of the gap 746 along the width.

The facing portions of the peripheral side walls 742 b and 742 c of theadjacent scalloped portions 740 b and 740 c can include a taperedportion, a substantially parallel portion, or both. In the substantiallyparallel portion the peripheral side walls 742 b and 742 c of theadjacent scalloped portions 740 b and 740 c extend along the widthsubstantially parallel to each other such that the size of the gap 746is substantially constant. In the tapered portion the peripheral sidewalls 742 b and 742 c of the adjacent scalloped portions 740 b and 740 cflare away from each other along the width. As shown in the illustratedembodiment, the peripheral side walls 742 b and 742 c of the adjacentscalloped portions 740 b and 740 c can flare away from each otherlinearly such that a first gap angle 748 is defined. The first gap angle748 can be from about 45 degrees to about 135 degrees, or in anotherembodiment the first gap angle 748 can be about 90 degrees. In anotherembodiment the peripheral side walls 742 b and 742 c of the adjacentscalloped portions 740 b and 740 c can flare away from each othernonlinearly.

In addition to extending along the width of the plate, the gap 746 canextend along the thickness of the plate, for example the gap 746 canextend into the first surface 726 toward the second surface 728. In oneembodiment the peripheral side walls 742 b and 742 c of the adjacentscalloped portions 740 b and 740 c flare away from each other along thethickness of the implant body 710. As shown in the illustratedembodiment, the peripheral side walls 742 b and 742 c of the adjacentscalloped portions 740 b and 740 c can flare away from each otherlinearly such that a second gap angle 750 is defined. The second gapangle 750 can be from about 0 degrees to about 45 degrees, or in anotherembodiment the second gap angle 750 can be about 10 degrees. In anotherembodiment the peripheral side walls 742 b and 742 c of the adjacentscalloped portions 740 b and 740 c can flare away from each othernonlinearly along the thickness.

It should be noted that the illustrations and discussions of theembodiments shown in the figures are for exemplary purposes only, andshould not be construed limiting the disclosure. One skilled in the artwill appreciate that the present disclosure contemplates variousembodiments. It should be further appreciated that the features andstructures described and illustrated in accordance one embodiment canapply to all embodiments as described herein, unless otherwiseindicated. Additionally, it should be understood that the conceptsdescribed above with the above-described embodiments may be employedalone or in combination with any of the other embodiments describedabove.

What is claimed:
 1. A TTA system configured to maintain a tuberosity inan advanced position relative to a tibial body, the advanced positionbeing spaced cranially with respect to a first position when thetuberosity is integral with the tibial body, the TTA system comprising:an implant that includes an implant body, the implant body defining aproximal end portion that is configured to support the tuberosity in theadvanced position, a distal end portion that is configured to beattached to the tibial body, and an intermediate implant portion thatextends between the proximal end portion and distal end portion, theintermediate portion shaped so as to space the proximal end portioncranially with respect to the distal end portion a distance sufficientso as to maintain the tuberosity in the advanced position; a spacerconfigured and sized to fit at least partially within a gap disposedbetween the tuberosity and the tibial body when the distal end portionand the proximal end portion are attached to the tibial body and thetuberosity, respectively, the spacer including a spacer body, the spacerdefining a slot that extends through the spacer body; and a spacerfixation member that includes a first end portion configured to beattached to the tuberosity, a second end portion that is configured tobe attached to the tibial body, and an intermediate fixation portionextending between the first end and the second end, the intermediatefixation portion configured and sized to be at least partially receivedin the slot so as to couple the spacer fixation member to the spacer. 2.The TTA system according to claim 1, wherein the proximal end portiondefines a plurality of fastener holes each configured to receive afastener so as to attach the distal end portion to the tibial body. 3.The TTA system according to claim 1, wherein the distal end portiondefines a plurality of fastener holes each configured to receive afastener so as to attach the proximal end portion to the tuberosity. 4.The TTA system according to claim 1, wherein the first end portiondefines at least one fastener hole that is configured to receive afastener so as to attach the first end portion to the tuberosity.
 5. TheTTA system according to claim 1, wherein the second end portion definesat least one fastener hole that is configured to receive a fastener soas to attach the second end portion to the tibial body.
 6. The TTAsystem according to claim 1, wherein the slot is a first slot, and thespacer defines a plurality of second slots that extend into the spacerbody so as to permit bone growth when the spacer is disposed in the gap.7. The TTA system according to claim 6, wherein spacer body is elongatealong a longitudinal direction, and the second slots are each angledrelative to the longitudinal direction.
 8. The TTA system according toclaim 1, wherein the first end portion is angularly offset relative tothe second end portion.
 9. The TTA system according to claim 1, whereinthe spacer includes a plurality of resilient tines, each of theresilient tines configured to be moved toward one another when thespacer is disposed in the gap such that at least a portion of the spacerconforms to a shape of the gap.
 10. The TTA system according to claim 9,wherein the spacer includes a spacer body, the spacer defines at leastone first fastener hole that is configured to receive a fastener, the atleast one fastener hole extends into the spacer body, the intermediatefixation portion defines at least one second fastener hole, and thefastener is configured to be inserted through the at least one secondfastener hole and into the at least one fastener hole to couple thespacer fixation member to the spacer.
 11. The TTA system according toclaim 9, wherein the spacer includes a spacer body that defines an uppersurface and an opposed lower surface, and the lower surface defines asubstantially concave shape to facilitate movement of the resilienttines toward each other when the spacer is disposed in the gap.
 12. TheTTA system according to claim 1, wherein the proximal end portion iselongate along a first axis and the distal end portion is elongate alonga second axis and the first axis and the second are angularly offsetwith respect to each other.
 13. The TTA system according to claim 1,wherein the implant body includes a first surface configured to face thetibial body and the tuberosity, and a second surface opposite the firstsurface, the implant body further defining a first thickness measuredfrom the first surface to the second surface in the proximal endportion, a second thickness measured from the first surface to thesecond surface in the distal end portion, and a third thickness measuredfrom the first surface to the second surface in the intermediate implantportion, wherein the third thickness is less than at least one of thefirst and second thicknesses.
 14. The TTA system according to claim 13,wherein the third thickness is less than both the first and secondthicknesses.
 15. The TTA system according to claim 1, wherein theimplant body includes a first side surface and a second side surfaceopposite the first side surface, the implant body further defining afirst width measured from the first side surface to the second sidesurface in the proximal end portion, a second width measured from thefirst side surface to the second side surface in the distal end portion,and a third width measured from the first side surface to the secondside surface in the intermediate implant portion, wherein the firstwidth is less than at least one of the second and third widths.
 16. TheTTA system according to claim 15, wherein the first width is less thanboth the second and third widths.
 17. The TTA system according to claim1, wherein the implant body includes a first surface configured to facethe tibial body and the tuberosity, and a second surface opposite thefirst surface, the implant body further includes a scalloped portionextending out from the first surface, the scalloped portion including aperipheral side wall and a raised surface configured to face the tibialbody and the tuberosity.
 18. The TTA system according to claim 17,wherein the scalloped portion is a first scalloped portion, the implantbody further comprising a second scalloped portion, wherein theperipheral side walls of the first and second scalloped portions definea gap between a portion of the peripheral side walls that face eachother.
 19. The TTA system according to claim 1, further comprising a TTAadvancement assembly configured to advance the tuberosity from a firstposition to the advanced position relative to the tibial body after anosteotomy has been made between the tuberosity and the tibial body, theTTA advancement assembly comprising: an advancement body configured tobe coupled to the tibial body; and a distraction arm movably coupled tothe advancement body, the distraction arm configured to be coupled tothe tuberosity, such that the distraction arm is configured to movealong with the tuberosity relative to the tibial body.
 20. The TTAsystem according to claim 19, wherein as the distraction arm movesrelative to the advancement body, the advancement assembly provides anindication of how far the tuberosity has advanced from the firstposition toward the advanced position.
 21. The TTA system according toclaim 20, wherein advancement assembly further comprises a displacementscale coupled to the advancement body, the displacement scale configuredto provide the indication.
 22. The TTA system according to claim 19,further comprising an angular adjustment member coupled to theadvancement body at an attachment location of the advancement body,wherein the angular adjustment member is configured to pivot relative toa pivot axis defined by the attachment location, the angular adjustmentmember including a contact member that is configured to fit in a gapdefined by the osteotomy and disposed between the tuberosity and thetibial body.
 23. A TTA advancement assembly configured to advance atuberosity from a first position to an advanced position relative to atibial body after an osteotomy has been made between the advancedtuberosity and the tibial body, the advanced position being spacedcranially and proximally with respect to the first position when thetuberosity is integral with the tibial body, the TTA advancementassembly comprising: an advancement body that is configured to becoupled to the tibial body; and a distraction arm movably coupled to theadvancement body, the distraction arm configured to be coupled to thetuberosity, wherein the distraction arm is configured to move along withthe tuberosity relative to the tibial body, such that the distractionarm moves a predetermined distance relative to the advancement body,wherein translation of the distraction arm the predetermined distancecauses the advancement assembly to provide an indication that thetuberosity has advanced from the first position to the advancedposition.
 24. The TTA advancement assembly according to claim 23,further comprising a displacement scale that is configured to providethe indication that the tuberosity has advanced from the first positionto the advanced position, wherein the displacement scale is coupled tothe advancement body, the displacement scale is disposed substantiallyparallel to the distraction arm so as to measure the translation of thedistraction arm when the distraction arm is moved relative to theadvancement body.
 25. The TTA advancement assembly according to claim23, further comprising an angular adjustment member coupled to theadvancement body at an attachment location of the advancement body,wherein the angular adjustment member is configured to pivot relative toa pivot axis defined by the attachment location, the angular adjustmentmember includes a contact member that is configured to fit in a gapdefined by the osteotomy and disposed between the tuberosity and thetibial body such that the distraction arm is oriented at a predeterminedadvancement angle relative to the osteotomy.
 26. The TTA advancementassembly according to claim 25, wherein the angular adjustment member isconfigured to be angularly fixed relative to the advancement body. 27.The TTA advancement assembly according to claim 23, further comprisingan implant that is configured to be attached to the tuberosity and thetibial body, and the implant being configured to be coupled to thedistraction arm such that movement of the distraction arm relative tothe advancement body causes at least apportion of the implant to movealong with the tuberosity relative to the tibial body.
 28. The TTAadvancement assembly according to claim 27, further comprising a drillguide that is configured to be attached to the implant, and thedistraction arm define a drill guide hole that is configured to receivethe drill guide so that the drill guide is configured to be coupled tothe distraction arm and the implant when the drill guide is insertedthrough the drill guide hole and is attached to the implant.
 29. The TTAadvancement assembly according to claim 23, wherein the advancement bodydefines an opening configured to receive a wire such that theadvancement body can be coupled to the tibial body when the wire isinserted through the opening and into the tibial body.
 30. The TTAadvancement assembly according to claim 23, wherein the advancement bodyis configured as a jig.
 31. A TTA method to configured to advance atuberosity from a first position to an advanced position relative to atibial body after an osteotomy has been made between the advancedtuberosity and the tibial body, the advanced position being spacedcranially and proximally with respect to the first position when thetuberosity is integral with the tibial body, the method comprising:coupling an advancement body to the tuberosity via a distraction armthat is movably coupled to the advancement body, the distraction armconfigured to move relative to the advancement body; placing a contactmember that is coupled to the advancement body in a gap formed duringthe osteotomy, the gap disposed between the tuberosity and the tibialbody; moving the distraction arm relative to the advancement body tomove the tuberosity between the first position and the advancedposition.
 32. A TTA advancement assembly configured to advance atuberosity from a first position to an advanced position relative to atibial body after an osteotomy has been made between the advancedtuberosity and the tibial body, the advanced position being spacedcranially and proximally with respect to the first position when thetuberosity is integral with the tibial body, the TTA advancementassembly comprising: an advancement body that is configured to becoupled to the tibial body; and an angular adjustment member pivotallycoupled to the advancement body such that the angular adjustment memberis configured to pivot relative to the advancement body about a pivotaxis, the angular adjustment member including a contact member that isconfigured to fit in a gap defined by the osteotomy, wherein the angularadjustment member is configured to be pivotally fixed relative to theadvancement body such that advancement body is oriented at apredetermined advancement angle relative to the osteotomy when thecontact member is disposed in the osteotomy.
 33. The TTA advancementassembly according to claim 32, further comprising a distraction armmovably coupled to the advancement body, the distraction arm configuredto be coupled to the tuberosity, wherein the distraction arm isconfigured to translate to move along with the tuberosity relative tothe tibial body, such that the distraction arm moves a predetermineddistance relative to the advancement body.
 34. The TTA advancementassembly according to claim 32, wherein the angular adjustment memberincludes an angular scale that is configured to determine when theangular adjustment member is oriented at the predetermined advancementangle relative to the osteotomy.
 35. The TTA advancement assemblyaccording to claim 32, wherein advancement body is configured as a jig.36. The TTA advancement assembly according to claim 32, wherein thecontact member defines a substantially planar configuration.
 37. The TTAadvancement assembly according to claim 36, wherein the contact memberis configured as a blade.